[Python-checkins] cpython (merge 3.5 -> 3.6): Issue #27517: LZMA compressor and decompressor no longer raise exceptions if

Mon Oct 31 02:36:06 EDT 2016

https://hg.python.org/cpython/rev/fb64c7a81010
changeset: 104843:fb64c7a81010
branch: 3.6
parent: 104840:f43078ec598c
parent: 104842:b06f15507978
user: Serhiy Storchaka <storchaka at gmail.com>
date: Mon Oct 31 08:31:13 2016 +0200
summary:
 Issue #27517: LZMA compressor and decompressor no longer raise exceptions if
given empty data twice. Patch by Benjamin Fogle.
files:
 Lib/test/test_lzma.py | 38 +++++++++++++++++++++++++++++++
 Misc/ACKS | 1 +
 Misc/NEWS | 3 ++
 Modules/_lzmamodule.c | 5 ++++
 4 files changed, 47 insertions(+), 0 deletions(-)

diff --git a/Lib/test/test_lzma.py b/Lib/test/test_lzma.py
--- a/Lib/test/test_lzma.py
+++ b/Lib/test/test_lzma.py
@@ -137,6 +137,21 @@
 self.assertTrue(lzd.eof)
 self.assertEqual(lzd.unused_data, b"")
 
+ def test_decompressor_chunks_empty(self):
+ lzd = LZMADecompressor()
+ out = []
+ for i in range(0, len(COMPRESSED_XZ), 10):
+ self.assertFalse(lzd.eof)
+ out.append(lzd.decompress(b''))
+ out.append(lzd.decompress(b''))
+ out.append(lzd.decompress(b''))
+ out.append(lzd.decompress(COMPRESSED_XZ[i:i+10]))
+ out = b"".join(out)
+ self.assertEqual(out, INPUT)
+ self.assertEqual(lzd.check, lzma.CHECK_CRC64)
+ self.assertTrue(lzd.eof)
+ self.assertEqual(lzd.unused_data, b"")
+
 def test_decompressor_chunks_maxsize(self):
 lzd = LZMADecompressor()
 max_length = 100
@@ -274,6 +289,16 @@
 lzd = LZMADecompressor(lzma.FORMAT_RAW, filters=FILTERS_RAW_4)
 self._test_decompressor(lzd, cdata, lzma.CHECK_NONE)
 
+ def test_roundtrip_raw_empty(self):
+ lzc = LZMACompressor(lzma.FORMAT_RAW, filters=FILTERS_RAW_4)
+ cdata = lzc.compress(INPUT)
+ cdata += lzc.compress(b'')
+ cdata += lzc.compress(b'')
+ cdata += lzc.compress(b'')
+ cdata += lzc.flush()
+ lzd = LZMADecompressor(lzma.FORMAT_RAW, filters=FILTERS_RAW_4)
+ self._test_decompressor(lzd, cdata, lzma.CHECK_NONE)
+
 def test_roundtrip_chunks(self):
 lzc = LZMACompressor()
 cdata = []
@@ -284,6 +309,19 @@
 lzd = LZMADecompressor()
 self._test_decompressor(lzd, cdata, lzma.CHECK_CRC64)
 
+ def test_roundtrip_empty_chunks(self):
+ lzc = LZMACompressor()
+ cdata = []
+ for i in range(0, len(INPUT), 10):
+ cdata.append(lzc.compress(INPUT[i:i+10]))
+ cdata.append(lzc.compress(b''))
+ cdata.append(lzc.compress(b''))
+ cdata.append(lzc.compress(b''))
+ cdata.append(lzc.flush())
+ cdata = b"".join(cdata)
+ lzd = LZMADecompressor()
+ self._test_decompressor(lzd, cdata, lzma.CHECK_CRC64)
+
 # LZMADecompressor intentionally does not handle concatenated streams.
 
 def test_decompressor_multistream(self):
diff --git a/Misc/ACKS b/Misc/ACKS
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -452,6 +452,7 @@
 Tom Flanagan
 Matt Fleming
 Hernán Martínez Foffani
+Benjamin Fogle
 Artem Fokin
 Arnaud Fontaine
 Michael Foord
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -30,6 +30,9 @@
 Library
 -------
 
+- Issue #27517: LZMA compressor and decompressor no longer raise exceptions if
+ given empty data twice. Patch by Benjamin Fogle.
+
 - Issue #28549: Fixed segfault in curses's addch() with ncurses6.
 
 - Issue #28449: tarfile.open() with mode "r" or "r:" now tries to open a tar
diff --git a/Modules/_lzmamodule.c b/Modules/_lzmamodule.c
--- a/Modules/_lzmamodule.c
+++ b/Modules/_lzmamodule.c
@@ -521,6 +521,8 @@
 Py_BEGIN_ALLOW_THREADS
 lzret = lzma_code(&c->lzs, action);
 data_size = (char *)c->lzs.next_out - PyBytes_AS_STRING(result);
+ if (lzret == LZMA_BUF_ERROR && len == 0 && c->lzs.avail_out > 0)
+ lzret = LZMA_OK; /* That wasn't a real error */
 Py_END_ALLOW_THREADS
 if (catch_lzma_error(lzret))
 goto error;
@@ -896,6 +898,9 @@
 PyObject *result;
 lzma_stream *lzs = &d->lzs;
 
+ if (lzs->avail_in == 0)
+ return PyBytes_FromStringAndSize(NULL, 0);
+
 if (max_length < 0 || max_length >= INITIAL_BUFFER_SIZE)
 result = PyBytes_FromStringAndSize(NULL, INITIAL_BUFFER_SIZE);
 else
-- 
Repository URL: https://hg.python.org/cpython
